Seagate, WD improve SATA drives

Posted on August 15, 2005

— Seagate and Western Digital recently began production shipments of Serial ATA (SATA) drives designed for non-desktop applications. For example, Seagate today began shipments to the channel of its NL35 line of "nearline" SATA drives, which were announced in October 2004.

In terms of reliability, the NL35 SATA drives (which are also available with Fibre Channel interfaces) fall between desktop SATA drives and higher-end drives such as SCSI, Serial Attached SCSI (SAS), and Fibre Channel. For example, the mean time between failure (MTBF) rating for the NL35 SATA drives is one million hours, compared to 700,000 hours for Seagate's desktop SATA drives and 1.4 million hours for Seagate's higher-end disk drives.

In terms of performance, the nearline SATA drives are similar to Seagate's desktop SATA drives. For example, both have a rotation speed of 7,200rpm and a data transfer rate of 1.5Gbps. That compares to 15,000rpm for Seagate's high-end Cheetah Fibre Channel drives.

The main differences between Seagate's desktop Barracuda SATA drives and nearline NL35 SATA drives, other than the MTBF ratings, are that the nearline versions include a reliability feature called Workload Management, as well as a number of features that make the drives easier to integrate in multi-drive arrays, including Error Recovery Control, One-Step Microcode Download, and Write-Same Technology.

The NL35 SATA drives include 8MB or 16MB of cache and have an average seek time of 8 milliseconds for reads and 9msec for writes.

The NL35 drives are available in 250GB or 400GB capacities. Production shipments of a 500GB version are slated for the fourth quarter. (Hitachi and Maxtor are currently shipping 500GB SATA drives.)

Pricing depends on Seagate's channel partners, but the NL35 SATA drives are expected to cost about 10% more than Seagate's desktop Barracuda SATA drives.

Meanwhile, Western Digital recently began shipping 7,200rpm, 400GB Caviar RE2 (RAID Edition) disk drives that WD rates at an MTBF of 1.2 million hours. The drives are targeted at server and NAS systems.